Quantel Pablo 3D or how not to lose your mind with stereoscopy

Quantel's development to manage 3D stereo in real time on its Pablo system has made stereoscopic film post-production a viable alternative for the first time. Pablo, with stereo capability, became the first system available powerful enough to allow directors and editors to view two streams simultaneously, at full resolution, make necessary adjustments instantly, in real time, and see the results of the stereo 3D changes immediately on screen.

Quantel's stereo 3D post-production technology has made interactive stereoscopic 3D post-production a practical proposition for the first time. In doing so, it created a great new business opportunity for television and post-production companies, offering producers a powerful weapon to attract audiences and increase profits.

A Pablo digital grading system from Quantel, equipped with 3D stereo technology at Fotokem in Los Angeles, allowed Disney to bring the 74-minute concert film in stereo to US theaters in just 11 weeks from filming. 3D Hannah Montana & Miley Cyrus: Best of Both Worlds, which was filmed in two concerts of the tour. The result was that Disney capitalized on the audience's interest by releasing the film just a few days after the tour ended, and recording an all-time record for ticket sales in a single weekend.

Numerous Pablos equipped with the Quantel 3D stereo option have already been sold around the world, and all of them are being used intensively in the production of 3D work around the world. The key to this novel development from Quantel in terms of stereo 3D technology is that it allows users to work simultaneously on both “eyes”, playing back, editing and adjusting stereo parameters in real time, at the original resolution (HD or 2K, per eye). This is possible thanks to the combination of innovative software tools with the enormous hardware power of Pablo.

Before the advent of Quantel stereo 3D technology, post-production had to be carried out on each eye separately. This proved to be an insurmountable barrier to producing stereo 3D content within reasonable timeframes and budgets.

3D in real time

The main novelty in terms of the application and technical aspects of the stereo 3D technology developed by Quantel is that it allows reviewing and manipulating streams of twin high-resolution stereo images, simultaneously and in real time. The suite of 3D tools, combined with the power of the Pablo systems on which it runs, dramatically reduces the time required to produce stereoscopic 3D results, and allows the user to overcome problems that previously made it difficult to view stereo 3D images. These included nausea and headaches usually caused by the difference between “both eyes,” or rapid changes in convergence between planes. Pablo 3D, thanks to the convergence and adjustment control, avoids undesirable stereo effects, smoothing convergence changes between planes and making viewing a pleasant experience.

On the other hand, it allows the balancing of both eyes interactively, using a combination of 3D stereo tools and Pablo's nonlinear color correction toolset. Adjusting the colors between stereo streams is vital to offer the viewer a pleasant experience, otherwise the viewer's brain will try to adjust the inconsistencies between two streams, with the consequent headaches and fatigue.

By editing both streams simultaneously, 3D editing becomes as simple as 2D. However, the editing style required for 3D can be very different from that needed for 2D, requiring fewer cuts and smoother transitions between shots to avoid viewer fatigue. By editing and reviewing 3D stereo material interactively the editor can naturally avoid such problems. This is not only necessary for feature films but also essential and vital for the near-live broadcast of images in stereoscopic 3D.

Pablo 3D interface example (screen grab)

Tools

Because recorded images for each eye are viewed simultaneously, synchronization problems between the two can be quickly identified and resolved. In comparison mode, the user can see and analyze the differences between eyes to solve those problems quickly. Tools include a 50/50 mix, left/right eye, and difference map. Spatial geometry tools allow you to interactively resolve inaccuracies between frames of one eye and the other.

3D stereo does not produce a single result that fits all screens. The way the image should be framed varies, depending on the relative size of the screen being used. For example, projecting on a giant movie screen is not the same as projecting on a home television. Quantel's 3D stereo toolset allows you to create different versions and perform playout in real time.

On the other hand, the lens splitters used in many 3D stereo cameras incorporate variations in chroma and luma for each frame, and these are different for each eye. Quantel's 3D stereo toolset includes a plug-in that quickly and easily corrects the problem within each frame and between each stereo pair.

In addition to solving the usual post-production problems, such as glare or dirt, Quantel's 3D stereo tools also allow you to quickly solve typical 3D stereo problems, using Pablo's VFX and Paint features. Edge effects have proven to be a major problem when, for example, an object in the front of the screen disappears from one eye of the viewer in a different frame than the other, resulting in distraction and therefore uncomfortable viewing. These types of issues are easily identified with Quantel's 3D stereo review tools, allowing you to compare each pair of stereo frames and resolve any edge effects issues that are identified.

Fotokem team during the 3D post-production of the film Hannah Montana (Photo: Quantel)

a revolution

The arrival of digital acquisition and new technologies applied to screens have eliminated two of the three main barriers to the widespread adoption of 3D as a viable creative and business proposition, both for feature films and television. But until Quantel's introduction of its stereo 3D technology, post-production remained a major problem, limiting the potential of 3D to a few specialized areas.

As 3D stereo consists of two parallel media streams, at high resolution, post-production demands a very high capacity of processing power. Until now, the only way to carry out post-production was to work individually on a single eye, and then take the results to the server and check the stereo result. This made post-production really complicated, and consumed a lot of time and resources. In practice, 3D was very difficult to produce and almost impossible to do well.

While a “more or less good” work may be acceptable in many media, in the case of 3D it is not, given the tremendous demands it represents on the viewer's brain. Any disparity between the two eyes (synchronization, color, geometry) can make it very difficult to see without experiencing discomfort, from nausea to headaches. This can be exacerbated by frequent changes in convergence, requiring the eyes to make an apparent change in accommodation. Until now, these reasons, together with the prohibitive cost of trying to solve these types of problems with traditional 2D technologies, had reduced the potential use of stereoscopic 3D.

All of these problems can be completely avoided by working in post-production on both eyes simultaneously. The editor naturally performs convergence at comfortable ratios, and differences between eyes can be corrected interactively as they are discovered throughout the post-production process. That is precisely the need that Quantel satisfied with its 3D stereo technology in alliance with its Pablo system. Production times and costs are significantly reduced, making stereo 3D post-production, for the first time, a truly viable creative and business opportunity. As John Nicolard of FotoKem explained about his company's work in Hannah Montana: “If we had not had Quantel's 3D convergence capabilities at our disposal, we would never have been able to finish this job on time.”

The result: a new form of production that is gaining ground not only in cinema but also in television, presenting itself as an opportunity to 'rescue' audiences.